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CPU modes (also called processor modes, CPU states, CPU privilege levels and other names) are operating modes for the central processing unit of some computer architectures that place restrictions on the type and scope of operations that can be performed by certain processes being run by the CPU.
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periodic(8) [freebsd man page]

PERIODIC(8)						    BSD System Manager's Manual 					       PERIODIC(8)

NAME
periodic -- run periodic system functions SYNOPSIS
periodic directory ... DESCRIPTION
The periodic utility is intended to be called by cron(8) to execute shell scripts located in the specified directory. One or more of the following arguments must be specified: daily Perform the standard daily periodic executable run. This usually occurs early in the morning (local time). weekly Perform the standard weekly periodic executable run. This usually occurs very early on Saturday mornings. monthly Perform the standard monthly periodic executable run. This usually occurs on the first day of the month. security Perform the standard daily security checks. This is usually spawned by the daily run. path An arbitrary directory containing a set of executables to be run. If an argument is an absolute directory name it is used as is, otherwise it is searched for under /etc/periodic and any other directories specified by the local_periodic setting in periodic.conf(5) (see below). The periodic utility will run each executable file in the directory or directories specified. If a file does not have the executable bit set, it is silently ignored. Each script is required to exit with one of the following values: 0 The script has produced nothing notable in its output. The <basedir>_show_success variable controls the masking of this output. 1 The script has produced some notable information in its output. The <basedir>_show_info variable controls the masking of this output. 2 The script has produced some warnings due to invalid configuration settings. The <basedir>_show_badconfig variable controls the mask- ing of this output. >2 The script has produced output that must not be masked. If the relevant variable (where <basedir> is the base directory in which the script resides) is set to ``NO'' in periodic.conf, periodic will mask the script output. If the variable is not set to either ``YES'' or ``NO'', it will be given a default value as described in periodic.conf(5). All remaining script output is delivered based on the value of the <basedir>_output setting. If this is set to a path name (beginning with a '/' character), output is simply logged to that file. newsyslog(8) knows about the files /var/log/daily.log, /var/log/weekly.log and /var/log/monthly.log, and if they exist, it will rotate them at the appropriate times. These are therefore good values if you wish to log periodic output. If the <basedir>_output value does not begin with a '/' and is not empty, it is assumed to contain a list of email addresses, and the output is mailed to them. If <basedir>_show_empty_output is set to ``NO'', then no mail will be sent if the output was empty. If <basedir>_output is not set or is empty, output is sent to standard output. ENVIRONMENT
The periodic utility sets the PATH environment to include all standard system directories, but no additional directories, such as /usr/local/bin. If executables are added which depend upon other path components, each executable must be responsible for configuring its own appropriate environment. FILES
/etc/crontab the periodic utility is typically called via entries in the system default cron(8) table /etc/periodic the top level directory containing daily, weekly, and monthly subdirectories which contain standard system peri- odic executables /etc/defaults/periodic.conf the periodic.conf system registry contains variables that control the behaviour of periodic and the standard daily, weekly, and monthly scripts /etc/periodic.conf this file contains local overrides for the default periodic configuration EXIT STATUS
Exit status is 0 on success and 1 if the command fails. EXAMPLES
The system crontab should have entries for periodic similar to the following example: # do daily/weekly/monthly maintenance 0 2 * * * root periodic daily 0 3 * * 6 root periodic weekly 0 5 1 * * root periodic monthly The /etc/defaults/periodic.conf system registry will typically have a local_periodic variable reading: local_periodic="/usr/local/etc/periodic" To log periodic output instead of receiving it as email, add the following lines to /etc/periodic.conf: daily_output=/var/log/daily.log weekly_output=/var/log/weekly.log monthly_output=/var/log/monthly.log To only see important information from daily periodic jobs, add the following lines to /etc/periodic.conf: daily_show_success=NO daily_show_info=NO daily_show_badconfig=NO DIAGNOSTICS
The command may fail for one of the following reasons: usage: periodic <directory of files to execute> No directory path argument was passed to periodic to specify where the script fragments reside. <directory> not found Self explanatory. SEE ALSO
sh(1), crontab(5), periodic.conf(5), cron(8), newsyslog(8) HISTORY
The periodic utility first appeared in FreeBSD 3.0. AUTHORS
Paul Traina <pst@FreeBSD.org> Brian Somers <brian@Awfulhak.org> BUGS
Since one specifies information about a directory using shell variables containing the string, <basedir>, <basedir> must only contain charac- ters that are valid within a sh(1) variable name, alphanumerics and underscores, and the first character may not be numeric. BSD
August 30, 2007 BSD

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